Coating fuel to prevent dusting and product thereof



Patented Apr. 27, 1937 COATING FIlEL 'ro PREVENT DUSTING ANDY PRODUCT THEREOF Per; KlFrolich, Elizabeth, N. J., assignor to Standard Oil Development Company, a corporation of Delaware No Drawing. Application December 12, 1931, Serial N0. 580,738

12 Claims.

This invention ,relates to improvements in methods of treating solid fuels (coal, coke, briquets, and thelike) with substances adapted to render the fuels relatively non-dusting. For

this and other purposes according to the present invention sulfonic acid compounds derived from petroleum, naphthalene sulfonic acids, and the i like, are used, either as such or in the form of their salts. These compounds lay the dust present at the time of treatment and prevent or retard surface disintegration or slacking of the fuels.

The terms sulphonic compound and sulfonate are used herein and in the claims to sig- 'nify acidic compounds of the type-obtained by possess the following properties which make them desirable fortreating fuels:

These compounds form tenacious films over 5 the fuel surface.

material and do not result in objectionable smoke production. They are substantially without odor and under normal conditions of use they do not corrode metals. nor cause any injury to thosehandlingthe fuel. They can be applied in solution (aqueous or organic solvent) by ordinary spray methods. They I are available in many oil refineries as waste materials which can be obtained very cheaply. .The aqueous solutions applied can be sufficiently concentrated to prevent danger of freezing and binding of the fuel lumps together, or suitable freezing point depressants may be added,'e. gi sodium chloride, 40 molasses, etc. When oil solutions are used, substances tending to lower the pour point may be added, for example the substances described in the United States Patent No. 1,815,022 to G. H. B. Davis, granted July 14, 1931. When dried upon the fuel in presence of air. the's'ulfonic compounds are not readily dissolved by contact with water. The blackness and luster' usual spraying means.

They do not retard combus-' tion. They add slightly to the fuel value of the Coal, coke, briquets or the like which have Coal which has been previously artificially colored may also betreated with these sulfonic compounds in order to prevent dusting. In this case the amount of treating material used is not sufficient to completely cover all of the coal particles, thus leaving some of the characteristic coloring material to act as a distinguishing feature.

I am aware that various substances having certain of the above-mentioned properties have been used heretofore to make solid fuels nondusting, for example, mineral oils as such, emul-- sified mineral oils, magnesium chloride, calcium chloride, etc.

In accordance with the present invention the improved treating agents may beapplied by any This is in general preferred although the fuel may be immersed in the solution or otherwise brought into contact with it. An advantageous way of carrying out the invention is to prepare a 5-15% solution of the sulfonic compound in water (referring first to water soluble compounds) and spray it on the coal or other fuel as it passes through therotary sizing screens. For example, a solution of 15% of sodium sulfonate derived from petroleum and slightly acid is desirable. Generally, about to 2 pounds of solid sulfonic compounds in solution are necessary for treating one ton of coal to form a satisfactory superficial layer over the lumps. A somewhat larger quantity is required for treating coke or other absorptive fuel. The treating agent is most conveniently supplied to the trade in concentrated form, say about 45% sulfonic compounds and water. This material especially the'neutralized sulfonic acids, may also be dried by a spray drier or the like and the powder dissolved in the necessary amount of water at the place where the fuel is to be treated.

In the foregoing description reference has been made to' ;the water solublesulfonic compounds which are well known products of the treating of heavy petroleum fractions with fuming or concentrated sulfuric acid for the manufacture of white oils and certain lubricating oils.

. These sulfonic compounds are separated in the sludge from the acid-treatment. The sludge is washed with water with or without the addition of live steam and the acids are used as such or after neutralizing them with a suitable base which may be an alkali or alkaline earth metal (herein referred to generally as alkali), preferably sodium or calcium. It is highly advantageous to remove as much sulfuric acid by such 35 material:

treatment as possible, not only because of the corrosive action of the latter and the increase in viscosity which it gives the solution, but also because of the white coloration produced by the 5 sodium sulfate when a neutralized sludge is allowed to dry on the fuel. Generally, the sulfuric acid content should be controlled to between 2.15%. I

The oil soluble sulfonic compounds are also suitable for making coal non-dusting.

compounds are retained by the oil after the sulfuric acid treatment and are removed from the oil by washing with an organic solvent such as isopropyl alcohol; The alcohol solution containing sulfonic acids maybe used either with or without completely or partially neutralizing the sulfonic acids, for treating coal and other fuels. Alternatively, the sulfonic acids or their salts may be separated and supplied either in alcohol or water solution or in alcohol-water solution. An equivalent method is to dissolve the sulfonic compounds in gas oil or other hydrocarbon oil the use of which would not involve an undue fire hazard when spraying solid fuel. When the fire hazard is not a' consideration, low boiling oils such as gasoline, naphtha, etc., may be used as solvents for the sulfonic compounds. V The method described above is satisfactory for sulfonic. acids obtained by treating lubricating oil (white oil) fractions with sulfuric acid. However, when another fraction of petroleum oil,

such as bottoms stock, (cylinder stock, etc), is

treated with sulfuric acid, the following procedure is adopted to make a suitable coal treating The sludge is first washed with a small amount of water to remove sulfuric acid. The sulfuric acid .(bottom layer) is drawn off, additional water is added to the top layer and the water soluble sulfonic acids are, extracted .40 and may be used directly as such or partially neutralized to treat solid fuel. i

If necessary, the solventfor the sulfonic. compounds may be heated to any temperature short of its atmospheric boiling point, or heated under 45 pressure, to bring the sulfonic compounds readily The sulfonic compounds are capable of carry- I These Thepresence of other substances is not ing dyes of various kinds and fuels may be simultaneously dyed and rendered non-dusting.

Various changes and alternative compositions may be adopted within the scope of the appended claims in which it is my intention to claim all novelty inherent in the invention as broadly as the prior art permits.

fonic .compound' derived from acid, treated.

petroleum, adapted to retard the formation of dust, and substantially free of tar.

3. Method of treating solid carbonaceous fuels comprising coating them with a material selected from the class consisting of sulfonic acids separated from acid treated petroleum and their neutralized products.

4. Method of treating solid carbonaceous fuels comprisingicoating them with water-soluble sulfonates separated from acid treated petroleum and substantially free of tar. I

5. Method of treating solid carbonaceous fuels comprising coating them with a water suspension of oil-soluble sulfonates derived from acid treated petroleum.

6. 'Method of treating 011c carbonaceous fuels f comprising coating them with hydrocarbon sulfonic compounds in the amount of /3 to 2- lbs. of solid sulfonic compounds per ton of fuel.

'7. Method of treatingsolid carbonaceous fuels 8. Method for inhibiting the dusting and surcomprising coating them with a water solution" containing 5 to 15% of hydrocarbon sulfonic compounds.

face slacking of coal and coke in lump form,

comprising wetting the surface of the lumps with an aqueous solution of a hydrocarbon sul'- phonate.

9.1 Method according to claim 8 in which said sulphonate is separated from awashed and neutralized petroleum acid sludge.

- 10. An improvedfuel composition comprising a solid fuel, the surface of which is coated with a sulphonic compound derived from petroleum,

by sulphuric acid treatment thereof and free from the major amount of tar and sulphuric acid.

11. A composition according to claim 10 in which the solid fuel' is coated with an aqueous 7, solution of a neutralized sulphonic compound.

12. A composition according to claim 10 in which the solid fuel is coated with a neutralized sulphonic compound in an organic solvent.

- PER, K. FROLICH. 

